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BIG PHYSICS, BIG QUESTIONS –

Biodiversity app logs insects by their telltale call

An app lets anyone log the numbers of endangered animals – by listening to their calls

By Paul Marks

Cicada to the right, 100 metres

(Image: Oscar Dominguez/Photoshot)

TO THE untrained ear, the chirping noises made by many small creatures or insects sound very similar. Now there is a new breed of app that will allow anyone with a smartphone to identify the unique calls of endangered animals, and keep an eye on biodiversity.

Assessing the numbers of a species in a certain area is painstaking, tiring work, particularly when the animal you are looking for is small – and extremely rare. The new app Cicada Hunt works much like Shazam, which samples short music clips to help identify a mystery song. This time, though, the software is listening out for the call of the endangered New Forest cicada, Cicadetta montana. The app could also be trained to detect many different animals, from birds and bats to grasshoppers and crickets.

Developed by Alex Rogers and a team at the University of Southampton, UK, Cicada Hunt was designed so that the millions of people who annually visit the New Forest, ancient woodland that lies west of Southampton, can help monitor how the cicada is faring.

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The idea is that tourists wander in the woods with the app running in the background on their smartphones. Once the app has recognised the insect’s call, it sounds an alert to tell the user to record a brief sound clip that can be emailed later to researchers, who then create a heat map of the insect’s spread.

The team was partly inspired by eBird, an American birdwatching network in which twitchers recognise and count rare birds in the field and use an app to send the data to researchers at Cornell University, New York. But Rogers’s team wanted the app to do the recognition work and tap into the power of the crowd.

Cicada Hunt is similar to a voice recognition system. “It has to easily differentiate between the cicada, which has a constant song, and other common insects, particularly the dark bush cricket, which chirps,” says Rogers. The system recognises C. montana by seeking out a ratio of two telltale wavelengths in its song.

The app recognises the rare New Forest cicada by seeking out two telltale wavelengths in its song

In tests on a known population in Slovenia, the app was easily able to detect cicada, says Rogers. The team is now updating it to identify 20 species of grasshopper and cricket, as well as birdsong. The app was presented at an artificial intelligence conference in Beijing, China, on 9 August.

It was born of a desire to take advantage of the power of smartphone-based sensing to broaden searches. For instance, Google has equipped the Surui tribe in the Brazilian Amazon with Android phones to let them track illegal logging.

Biologists like Kenichi Ueda of the website iNaturalist.org are pretty excited. “If their technique can be generalised to identify the sounds of any animal and not just cicadas, then I think the stage is set for some kind of Animal Shazam service that will tell you what crickets are chirping in your backyard, or what shrieking bird just woke you up at 4 am.”

This article appeared in print under the headline “The unsuspecting naturalist”